Treatment of fibrous materials



United States Patent 3,166,436 TREATMENT OF FIBRGUS MATERIAES Dorothy Joyce Guest,- Leslie Budworth Morgan, and John Bryn Owen, all of Manchester, England, assignors to Imperial Chemical Industries Limited, Millbanir, London, England, a corporation of Great Britain No Drawing. Filed June 25, 1962, Ser. No. 205,096 Claims priority, application Great Britain, July 11, 1961,

13 Claims. (Cl. 117-1395) This invention relates to the treatment of fibrous materials with an acrylonitrile polymer.

According to the present invention we provide a proc ess for the impregnation or coating of fibrous materials with a dispersion of p'olyacrylonitrile or a copolymer as hereinafter defined containing acrylonitrile in an aqueous solution of a high boiling solvent or plasticizer for polya-crylonitrile, or in the case of the copolymer containing acrylo-nitrile a high boiling solvent or plasticizer for the said copolymer, the concentration of said solvent or pla'sticizer being such that the aqueous solution in which the polymer is dispersed is not a solvent for polyacrylontrile and thereafter heating option-ally with or without application of pressure.

tBy fibrous materials we means textiles in all forms and also paper and leather. 7

By a copolymer containing acrylonitrile we mean a copolym-er which contains acrylonitrile and is soluble in 'thehigh boiling .solvent or plasticizer for the copolymer but is insoluble in the aqueous solution of the high boiling solvent or plasticizer for the oopolymer. Particularly suitable monomers which may be copclymerized with acrylonitrile include for example, acrylic and methacrylic acids and their esters.

The process of the invention is employed to impart valuable properties to the fibrous materials, for example to improve the fullness of handle or bulk or to confer dimensional stability and in the case of non-woven structures such as fibrous Webs the process may be used to bond the fibres together, to form etiher strong non-woven fabrics which subsequent to a flexing treatment have a soft handle and excellent drape or, depending on the amount of polymer deposited, its constitution and the use of heat and pressure, fibrous structures which may be leathenlike, paper-like or as rigid sheets.

The invention includes the treatment of cellulosic, proteinaceous and synthetic textile materials or mixtures thereof, with the plasticized polymer dispersions alone or together with polymers optionally containing reactive groups, with resin precondensates such as methyl-o1 and alkoxyme'thyl derivatives of nitrogen compounds which may for example be urea, melamine, triazines, tri-azones, imidazolidones, or other crease-resisting agents or together with formaldehyde or other known cross-linking agents whereby the wet and/or dry crease resistance and other properties of the textile materials are improved.

Furthermore, the process of the invention may be applied to chemically modified cellulosic or proteinaceous textile materials such as, for example, wool fibres or fabrics render-ed shrink resistant by processes that are used commercially such as chlorination, in order to confer otherdesirable properties such as, for example, improved resistance to abrasion. Alternatively, textile material's treated according to the invention may be subjected to conventional finishing operations, including, for example, treatment with ploymers or polymer precursors to confer specific properties such as improved water repellancy, resistance to abrasion and pilling, and, in the case of proteinaceous materials, treatment with setting agents such as sodium bisulphite and ammonium thioglycollate either to confer durable pleating or to set the fabric in the flat state.

As a further feature ofthe invention, there may be.

used in conjunction with the dispersions herein described structure is achieved. Such compounds include for ex ample water soluble salts of alginic acid, water soluble or dispersible cellulose derivatives and cationic polymers such as are prepared by the polymerization of diethylamincethyl methacrylate and quateruised with dimethyl sulphate.

Because acrylonitrile polymers are relatively inert and indifferent to the action of water and other common solvents fibrous material-s treated according to the process of the present invention have excellent resistance to washing and dry-cleaning and resistance to common organic solvents.

In the first stage of the process of the present invention the fibrous material is impregnated by conventional methof an acrylonitrile ploymer as hereinbefore described in 3 an aqueous solution of a solvent for polyacrylonitrile or the said copolymer, the said solvent having a boiling point greater than that of water. Solvents which are miscible with water and useful in the process of the present invention include ethylene and propylene carbonate, dime'thyl formamide, dimethyl acetamide, dimethyl sulp'hoxide, butyrolactone and concentrated aqueous solutions of thiocyanates.

The proportions of water and polymer solvent constituting the liquid phase of the dispersion may vary over wide limits depending upon the nature of the-solvent and the particular end effect required. The proportion of polymer solvent present must not be such that the water-polymer solvent mixture is itself a solvent for the polymer. Preferably the aqueous phase should contain between 5 to50% parts by weight of the polymer solvent, but smaller amounts of the polymer solvent are required, for example the aqueous phase may contain as little as 0.1% by weight, when the particular application requires that the concentration of polymer in the dispersion is low.

The concentration of polymer in the dispersion may be varied over wide limits depending on the amount of polymer required in the fibrous material and on the amount of dispersion which is retained by the fibrous material. The weight ratio of polymer to fibrous material may vary over a wide range depending on the amount of acrylonitrile in the polymer, the fibrous structure being treatedand the particular end effect required. The said dispersion may be prepared by any of the methods normally applicable to emulsion polymerization and additions of Water and/ or polymer solvent, as hereinbefore defined, may be made as required. It is advantageous in some cases to add the polymer solvent prior to polymerization, or alternatively the polymer solvent may be added at more than one stage for example before and after polymerization. The impregnation of the fibrous material may be effected for example either by immersion of the Patented Jan. 19, 1965 '3 all C. depending on the boiling point of the solvent used. The water present is readily volatilised and the higher boiling solvent which is less readily volatilized temporarily solubilizes or plasticizes the polymer retained by the fibrous material. The polymer-impregnated fibrous structure may at this stage be subjected to heat and pressure or it may be washed with water to remove the residual polymer solvent either without a heat and pressure treatment or after a heat and pressure treatment.

The application of dispersions of vinyl copolymers eont'aining acrylonitrile residues to fibrous structures to achieve various technical effects has already been proposed but if the polymers contain more than about 60% of aerylonitrile they are diflicult to soften and fuse, progressively higher temperatures and higher pressures being required as the acrylonitrile content of the copolymer is increased in order to obtain adhesion to the fibrous structure. When the acrylonitrile content is greater than 80% the removal of wated by evaporation merely results in a distribution of the copolymer in the fibrous structure as a non-adhering powder having little or no binding action on the individual fibres of the structure unless excessively high temperatures and pressures are applied. The use of a water-soluble high boiling polyacrylonitrile solvent in the aqueous polymerization dispersion according to the process of the present invention on the other hand results in greatly improved adhesion of the copolymer to the fibrous structure at lower temperatures and without high pressures.

It is possible to influence the properties of the materials obtained by the process of the present invention by varying the amount and type of monomer copolymerized with acrylonitrile. For example, more resilient structures are obtained if the acrylonitrile is copolymerized with a minor amount of ethyl acrylate or butyl methacrylate. Other monomers such as acrylic acid can be incorporated to improve the efiiciency of adhesion of the polyacrylonitrile to the fibrous material. The polymerization may also be conducted in an aqueous solution of a water soluble polymer such as polyacrylic acid, polyvinyl alcohol, polymethacrylamide and the like thereby giving graft copolymers which are equally suitable for the process of this invention.

The invention is illustrated but not limited by the following examples in which parts and percentages are by weight.

Example 1 A web of randomly disposed staple viscose rayon was immersed between wire gauze in a dispersion of 4 parts by weight of polyacrylonitrile in 20 parts of ethylene carbonate and 80 parts of water. The wire gauze containing the impregnated web was passed between squeezing rollers. The web was removed from the gauze and heated at 140 C. for 20 minutes and then extracted with boiling water to remove any residual ethylene carbonate and dried. The bonded fabric contained 35% of polyacrylonitrile. It had a soft pliable handle, subsequent to a flexing treatment, inter-fibre adhesion was good and was not destroyed by subjecting the fabric to either laundering or dry cleaning.

Example 2 A piece of wool flannel was immersed in a dispersion containing 8.2 parts of polyacrylonitrile, 20 parts of ethylene carbonate, 0.5 part of a sulphonated oil, and 71.3 parts of Water, and squeezed until the amount of dispersion retained was 160% of the weight of the dry fabric. The fabric was then heated at 6065 C. for 15 minutes and then at 140 C. for minutes.

After washing for 30 minutes in a dilute soap solution at 40 C., rinsing with warm water, and drying, the fabric which had increased in weight by 12%, was found to possess a full, soft handle.

, On milling in the presence of sodium oleate, the treated fabric was found to shrink by 11.5% of its original [gt area, whereas a similar untreated fabric shrank by 27%.

Example 3 A web of randomly disposed nylon and viscose rayon was immersed in a dispersion containing 2 parts of polyacrylonitrile, 4 parts of ethylene carbonate and 94 parts of water. The wire gauze containing the impregnated Web was passed between squeezing rollers so that the amount of liquor retained by the web was 1000% of its dry weight. The web was removed from the gauze and dried at C. followed by heating at C. for 10 minutes. The resulting fabric was then extracted with boiling water to remove any residual ethylene carbonate and dried. The bonded fabric had increased in weight by 18%.

After to break down the polymer film, the bonded fabric had a soft, pliable handle and adhesion was not destroyed on subjecting the fabric either to laundering or dry cleaning.

Example 4 When impregnating liquor of Example 3 contained 0.5 part of sodium alginate, the resulting fabric showed little evidence of migration of polymer or unsatisfactory bonding between polymer and fibrous web.

Example 5 When the impregnating liquor of Example 3 contained 0.5 part of a cationic polymer prepared by the polymerization of diethylaminoethyl methacrylate quaternized with dimethyl sulphate, the resulting fabric showed little evidence of polymer migration.

Example 6 A piece of wool flannel was immersed in a dispersion containing 10 parts of polyacrylonitrile, 20 parts of ethyle'ne carbonate, 0.5 part of a sulphonated oil, and 69.5 parts of water, and squeezed until the amount of dispersion retained was 125% of the weight of the dry fabric. The fabric was then heated at 80 C. for 20 minutes.

After washing for '20 minutes in a dilute soap solution at 40 C., rinsing with water, and drying, the fabric which had increased in weight by 12% was found to possess a full, soft handle.

On washing in the presence of soap and soda ash in a. domestic washing machine for 60 minutes, the treated fabric was found to shrink by 4% of its original area, whereas a similar untreated fabric shrank by 45%. Furthermore, the surface appearance of the treated pattern after washing was substantially the same as that of the untreated unwashed fabric.

The treated fabric was found to have improved resistance to abrasion and to pilling when compared with an untreated fabric.

Example 7 A piece of mercerised cotton poplin was immersed a dispersion containing 5 parts of an acrylonitrile/ethyl acrylate copolymer (50:50), 2.5 parts of ethylene carbonate, and 2.5 parts of water, and squeezed until the amount of dispersion retained was 80% of the weight of the dry fabric. The fabric which was then dried at 120 C. for 5 minutes, possessed a full handle which was substantially maintained on washing and dry clothing.

Example 8 'A piece of mercerized cotton poplin was immersed in a bath containing 25 parts of a dispersion containing 25 parts of an acrylonitrile/butyl acrylate copolymer (80:20), 8.3 parts of ethylene carbonate and 66.7 parts of water, 10 parts of a 50% aqueous solution of dimethyl ethyleneurea, and 0.8 part of zinc nitrate hexahydrate.

After squeezing so that the amount of liquor retained by the fabric was 80% of its dry weight, the fabric was dried at 6570 C., baked at C. for 3 minutes, and, finally washed-off in a solution containing 0.1%

7 of a non-ionic detergent and 0.1% soda ash at 60 C. for 5 minutes.

After rinsing and drying, the fabric which had improved resistance to creasing while in both the wet and dry state, was found to possess a full handle which was substantially maintained after repeated washing. Furthermore the fabric had improved resistance to abrasion as compared to that treated with the resin precondensate alone.

Example 9 Example 10 If in Example 9, the propylene carbonate was replaced by parts of dimethyl formamide, the resulting fabric possessed good fibre-to-fibre adhesion.

Example 1 1 If in Example 6, propylene carbonate was replaced by 20 parts of butyrolactone, the resulting fabric possessed good fibre-to-fi'ore adhesion.

What we claim is: i

1. A process for treating a fibrous organic material which comprises impregnating said fibrous material with a dispersion of (1) a polymer selected from the group consisting of homopolyrners of acrylonitrileand copolymers thereof which contain at least 50% by weight of acrylonitrile, in (2) a mixture which is not a solvent for said polymer and contains from 50 to 99.9% water and from 50 to 0.1% of a Water miscible. organic solvent for said polymer having a boiling pointgreater than water; evaporating the water from the fibrous material mer is a copolymer of acrylonitrile with a monomer selected from the group consisting of acrylic acid, methacrylic acid and lower alkyl esters of acrylic acid.

3. The process according to claim 1 wherein the organic solvent for said polymer is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl formamide, dimethyl acetamide, dimethylsulphoxide and butyrolactone.

4. The process according to claim 1 wherein said dispersion contains a polymer migration inhibitor selected from the group consisting of Water soluble salts of alginic acid and cationic polymers.

5. The process according to claim 1 wherein heating is conducted at a temperature of about 80 to 150 C.

6. The process according to claim -1 wherein evaporating the water and heating said fibrous material take place concurrently.

7. The process according to claim 1 wherein said heating includes the application of pressure to said material. 8. The process according to claim 1 wherein the fibrous material is a non-woven web of fibers.

References Cited by the Examiner v UNITED STATES PATENTS 2,3 5 0,03 2

/44 Hager. 2,781,243 2/57 Downing et a1. 260-29.6 X 2,886,473 5/59 Schroeder 117139.4 XR 2,982,753 5/ 61 Holmes et al 26032.4 XR 3,023,482 3/62 Gilboy et a1.

WILLIAM D. MARTIN, Primary Examiner. RICHARD D. NEVIUS, Examiner. 

1. A PROCESS FOR TREATING A FIBROUS ORGANIC MATERIAL WHICH COMPRISES IMPREGNATING SAID FIBROUS MATERIAL WITH A DISPERSION OF (1) A POLYMER SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS OF ACRYLONITRILE AND COPOLYMERS THEREOF WHICH CONTAIN AT LEAST 50% BY WEIGHT OF ACRYLONITRILE, IN (2) A MIXTURE WHICH IS NOT A SOLVENT FOR SAID POLYMER AND CONTAINS FROM 50 TO 99.9% WATER AND FROM 50 TO 0.1% OF A WATER MISCIBLE ORGANIC SOLVENT FOR SAID POLYMER HAVING A BOILING POINT GREATER THAN WATER; EVAPORATING THE WATER FROM THE FIBROUS MATERIAL IMPREGNATED WITH SAID DISPERSION THEREBY LEAVING A QUANTITY OF ORGANIC SOLVENT AND HEATING SAID FIBROUS MATERIAL IN THE PRESENCE OF SAID ORGANIC SOLVENT. 